package codingInterview.leetcode.editor.cn;

//定义一个函数，输入一个链表的头节点，反转该链表并输出反转后链表的头节点。 
//
// 
//
// 示例: 
//
// 输入: 1->2->3->4->5->NULL
//输出: 5->4->3->2->1->NULL 
//
// 
//
// 限制： 
//
// 0 <= 节点个数 <= 5000 
//
// 
//
// 注意：本题与主站 206 题相同：https://leetcode-cn.com/problems/reverse-linked-list/ 
// Related Topics 递归 链表 👍 389 👎 0

//Java：剑指 Offer 24 - 反转链表
public class FanZhuanLianBiaoLcof{
    public static void main(String[] args) {
                Solution solution = new FanZhuanLianBiaoLcof().new Solution();
        // TO TEST
    }
    
    //leetcode submit region begin(Prohibit modification and deletion)
/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int x) { val = x; }
 * }
 */
class Solution {
    public ListNode reverseList(ListNode head) {
        if(head==null) return null;
        ListNode node = head;
        ListNode nextBefore = node.next;
        while(nextBefore!=null){
            ListNode tmp = nextBefore.next;
            nextBefore.next = node;
            node = nextBefore;
            nextBefore = tmp;
        }
        head.next = null;
        return node;
    }
}
//leetcode submit region end(Prohibit modification and deletion)
public class ListNode {
    int val;
    ListNode next;
    ListNode(int x) { val = x; }
}
}
